Background: Ultrasonography is well-known for its application in medicine, and has been recently gaining importance for its use in the orofacial region. Aims and Objective: The present study aims to determine the efficacy of ultrasonography in diagnosing soft tissue swellings of the head and neck. Materials and Methods: Thirty patients with the head and neck soft tissue swelling were included in the study and all were subjected to ultrasonography. Various findings were recorded such as shape, boundary, echo-intensity, ultrasound architecture, presence of necrosis, posterior echoes, ultrasound characteristic of lesion, and vascularity, and an ultrasonography diagnosis was made. After obtaining final diagnosis sensitivity, specificity, positive predictive value (PPV), negative predictive value (NPV), and accuracy of the test was calculated in various types of swelling. Results: In case of an inflammatory swelling, ultrasonography had a sensitivity of 100%, specificity of 89.5%, PPV of 84.6%, NPV of 100%, and accuracy of 93.3%. In cystic swellings, ultrasonography had a sensitivity of 85.7%, specificity of 100%, PPV of 100%, NPV of 95.8%, and accuracy of 96.67%. In nonodontogenic benign tumor, ultrasonography had a sensitivity of 100%, specificity of 100%, PPV of 100%, NPV of 100%, and accuracy of 100%. In malignant swellings, ultrasonography had a sensitivity of 80%, specificity of 100%, PPV of 100%, NPV of 96.2%, and accuracy of 96.67%. Conclusion: From the present study, it can be concluded that ultrasonography is highly accurate in diagnosing benign neoplasms, followed by soft tissue cystic swellings and malignant neoplasms, followed by inflammatory swellings of the head and neck region.

Keywords: Color Doppler, swelling, ultrasonography

How to cite this article:Shah JS, Asrani VK. Clinical applications of ultrasonography in diagnosing head and neck swellings. J Oral Maxillofac Radiol 2017;5:7-13

Ultrasound is the name given to high-frequency sound waves, beyond or in excess of 20000 cycles per se cond (20 KHz). The term ultrasound means the form of sound energy beyond audible range.[1],[2],[3]

The technology for producing ultrasound imaging and the characteristics of sonic waves has been known for many years. Though the first attempt of practical application of ultrasound imaging was to search the sunken titanic in 1912, its medical application began after World War II in the late 1940s and early 1950s.[4]

The ultrasound signal transmitted into a patient is attenuated by a combination of absorption, reflection, refraction, and diffusion. The higher the frequency of the sound waves, the higher the image resolution but lesser penetration of the sound through soft tissue. The fraction of the beam that is reflected to the transducer depends on the acoustic impedance of the tissue, which is a product of its density (and thus the velocity of sound through it) and the beam's angle of incidence. Because of its acoustic impedance, a tissue has a characteristic internal echo pattern. Consequently, not only can changes in echo patterns distinguish between different tissues and boundaries but they also can be correlated with pathologic changes within a tissue. Tissues that do not produce signals, such as fluid-filled cysts, are said to be anechoicand appear black. Tissues that produce a weak signal are hypoechoic, whereas those that produce intense signals such as ligaments, skin, or needles, or catheters are hyperechoic and appear bright.[3]

In head and neck pathology, various investigations are available to reach a confirmatory diagnosis. However, conventional radiography has its limitation because of its two-dimensional view, other imaging modalities must be used to reach to diagnosis and ultrasonography (USG) is one of them.

USG is a diagnostic tool that is widely available, relatively inexpensive, noninvasive, and easily reproducible. It has several advantages over other modalities as it is harmless, uses no ionizing radiation, is widely available, easy-to-use, noninvasive, inexpensive, and unaffected by metal artefacts such as dental restorations. It can be performed without heavy sedation. Ultrasound causes no health problems and may be repeated as often as necessary.[2], 3, [5],[6],[7]

The present study aims to determine the role of USG and Doppler in diagnosing patients with head and neck soft tissue swellings, as well as differentiating inflammatory, cystic, benign, and malignant swellings.

Materials and Methods

After obtaining ethical committee clearance from institute, the study was conducted in the department among 30 patients to determine the USG findings of various soft tissue swellings in the head and neck region.

Inclusion criteria

Patient with head and neck swelling irrespective of age and sex were included in the study

Patient having head and neck swelling with systemic disease under ASA I and II were included in the study.

Exclusion criteria

Swellings owing to trauma or fracture were not included in the study

Swellings obscured by an overlying jaw bone were not included in the study

Patient having odontogenic cyst and tumor were not included in the study

Patient having systemic disease as per ASA III–VI.

Patients' detailed case history was recorded, and clinical examination was carried out on the basis of criteria given by Das.[8]

After clinical examination, certain investigations were carried out such as intraoral periapical radiograph, orthopantomograph, blood investigations, and urine investigations.

Based on the provisional diagnosis, swellings were divided into 4 groups as per their characteristics:

Inflammatory

Soft tissue cystic swelling

Nonodontogenic benign neoplasms

Malignant swellings

After provisional diagnosis, all patients were subjected to USGUSG investigation of each swelling was carried out in the Department of Radiology of B.J Medical College and Hospital using the ultrasonography machine Toshiba Istyle ™ and various probes available with different frequencies [Figure 1]. The following features were considered in describing the ultrasonography images of swelling in the head and neck, modified from Chandak et al.[2]

After USG findings, diagnosis was confirmed and treatment was planned accordingly. Following clinical and ultrasonography investigations, the diagnosis of swelling was confirmed either by fine needle aspiration cytology/biopsy and histologic confirmation. For inflammatory swelling, elimination of the cause either by incision and drainage or nonsurgical management was considered confirmatory. Positive results in computed tomography (CT)/CT angiography, magnetic resonance imaging (MRI), or MRI angiography was considered confirmatory for vascular lesions.

After obtaining the results, the data was statistically analyzed. Sensitivity, specificity, positive predictive value (PPV), negative predictive value (NPV), and accuracy of the test was calculated to evaluate the reliability and diagnostic efficacy of ultrasonography as an investigative tool.

Results

A total of 30 patients with head and neck swelling were included in the study [Table 1].

Out of 11 inflammatory swellings, 6 were diagnosed as swelling due to odontogenic cause, 1 as cellulitis, 1 as abscess, and 4 as space infection. Three were diagnosed as tuberculous lymphadenitis. Two were of salivary gland origin, 1 was acute bacterial Sialadenitis, and the other was Sjogren's syndrome. As per USG, 13 patients were suspected of inflammatory swelling, out of which 1 of them was soft tissue cyst and 1 was metastatic swelling [Table 2].

Table 2: Correlation between types of swelling and clinical, ultrasonographic, and histological diagnosis

In case of tuberculous lymphadenitis, lymph nodes may have round or oval shape, may appear as a lobulated due to matting of lymph nodes, and have additional central necrosis with loss of vascularity [Table 3] and [Figure 2].

Out of 7 cysts, 4 were nasolabial cyst, 2 were dermoid cyst, and 1 was branchial cleft cyst. As per USG, 6 out of 7 were diagnosed as soft tissue cyst while 1 was diagnosed as abscess [Table 2] and [Figure 3].

Figure 3: (a) Swelling in the neck of the patient on right side having Branchial cleft cyst. (b) USG findings of same patient misdiagnosed as abscess

Most of the cystic swellings have an oval shape, very clear boundaries, anechoic echo intensity, homogenous architecture, enhanced posterior echoes, with cystic tissue characteristics, and are avascular [Table 3]. Histological examination, i.e., either biopsy or fine needle aspiration cytology was considered final.

In case of cystic swellings, clinical diagnosis had a sensitivity of 100%, specificity of 95.6%, PPV of 87.5%, NPV of 100%, and accuracy of 96.67% while ultrasonography diagnosis had a sensitivity of 85.7%, specificity of 100%, PPV of 100%, NPV of 95.8%, and accuracy of 96.67% [Table 4].

Benign tumors

Out of 7 benign neoplasm, 5 were vascular neoplasms, 1 was lipoma, and 1 was salivary gland tumor. As per USG, 7 out of 7 were diagnosed as benign neoplasm [Table 2].

Most of the benign neoplasms have an oval shape, relatively clear boundaries (ill-defined in cases of vascular lesion), mixed echo intensity, heterogenous architecture, enhanced posterior echoes, mixed characteristics, and minimal vascularity (cystic characteristics and vascularity in case of vascular lesions) [Figure 4]. In 5 cases, vascular neoplasm Doppler USG revealed the type of vascular malformation; 2 were having slow flow were diagnosed as venous malformation, 2 had medium flow out of which one was diagnosed as arterial-venous malformation, whereas 1 as hemangioma with phlebolith and 1 had high flow was diagnosed as arterial malformation [Table 3] and [Figure 5]. In vascular lesions, CT angiography/MR angiography were considered as final diagnosis whereas in rest histological examination was considered as final diagnosis.

Figure 4: (a) Swelling over the left side of face of the patient. (b) USG of the same patient suggestive of pleomorphic adenoma

In 1 case, sonographic diagnosis did not match with final diagnosis. Clinically, 2 out 5 patients were suspected as malignant swelling, 1 as soft tissue cyst, and 2 were considered as inflammatory. As per USG, 4 out of 5 were diagnosed as malignant swelling, and 1 was diagnosed as inflammatory swelling [Table 3].

Most of the malignant swellings, have irregular shape, relatively clear boundaries, mixed echo intensity, heterogenous architecture, enhanced posterior echoes, mixed tissue characteristics, and avascular [Figure 6]. In case of metastatic lymphadenitis, along with other features of malignant swelling presence of central necrosis and loss of vascularity aids in making the diagnosis [Figure 7].

Figure 6: (a) Swelling in the floor of the mouth of the patient. (b) USG of the same patient suggestive of malignant mass

In case of malignant swellings, clinical diagnosis had sensitivity of 40%, specificity of 100%, PPV of 100%, NPV of 89.3%, and accuracy of 90%, while USG had sensitivity of 80%, specificity of 100%, PPV of 100%, NPV of 96.2%, and accuracy of 96.67% [Table 4].

Discussion

USG is indicated in various lesions of the jaw which includes soft tissues swellings, salivary gland disorders, lymph node disorders, malignant neoplasms, etc., Hence, swellings of the head and neck were categorized such as inflammatory, cystic, benign neoplasms, and malignant neoplasm for this study to evaluate the role of USG in diagnosing these swellings.

In the present study, 30 patients with obvious head and neck swelling were included, irrespective to age and sex. Patients with systemic disease coming under ASA I and II were included in the study as USG is a safe procedure and can be repeated many times without causing any damage to the body.[9]

In this study, swellings owing to trauma or fracture were not included because provisional diagnosis of hematoma is not a problem as there is history of trauma and changes in skin color and mucous membrane.[2]

Swellings obscured by an overlying jaw bone were not included, e.g., any pathology present in the deep lobe of the parotid gland not seen on the ultrasound as it is obscured by the ramus of the mandible.

Further odontogenic cysts and tumors were excluded because they can be easily diagnosed based on routine radiological investigation. Studies have been carried out by Summer et al.[10] Shahidi et al.[11]reported that USG does gives an idea about intrabony lesions, however, its histological correlation have not been carried out. Moreover, thick cortical plate overlying the swelling does not allow penetration of sound waves and makes it difficult to visualize the internal structure of the swelling.

In the present study, inflammatory swellings were more common followed by soft tissue cystic swellings and benign neoplasm, and lastly malignant swellings.

Most of the inflammatory swellings had relatively clear boundaries, oval shape, hypoechoic echo intensity, and homogeneous ultrasound architecture of lesion, which were found in our cases of cellulitis, space infection, and abscess.[2], 6, [12],[13],[14] Moreover, USG helped in determining the involvement of the spaces involved by infection.

Out of the three tuberculous lymphadenitis, 1 showed an oval shape, 1 round, and 1 lobular, with 2 having clear boundaries and 1 having unclear boundary with completely hypoechoic intensity and heterogeneous architecture with central necrosis, enhanced posterior echoes, mixed content, and no vascularity. Further, matting of the lymph nodes was noted which helped to diagnose tuberculous lymphadenitis [Table 3]. These findings were similar to that found by Ying and Ahuja [17] and Chandak et al.[2]

Cysts on the sonogram appear anechoic with a very clear boundary and homogeneous echo texture. If the cysts become infected, the content of the lesion can produce some echoes, producing hypoechoic structures.

In this study, 7 cases of soft tissue cysts were studied, out which 4 were nasolabial cyst which showed an oval shape with a well-defined boundary, anechoic content, completely homogenous with posterior enhancement of echoes with internal cystic characteristic, and were avascular. Two were dermoid cyst out of which 1 showed lobular shape and 1 oval shape with relatively clear boundary with hyperechoic intensity with homogenous architecture, along with enhancement of posterior echoes, 1 showed mixed internal content and 1 showed solid internal content with no vascularity [Table 3]. These findings were similar to those found by Wong et al.[18] and Chandak et al.[2]

Out of 7 soft tissue cyst, branchial cleft cyst was misdiagnosed ultrasonographically as abscess, as it was appearing as a collection of fluid, and certain times long standing abscess may give cystic appearance as found by Chandak et al.[2]

All the benign nonodontogenic tumors were correctly diagnosed provisionally as well as ultrasonographically. The USG findings were consistent with findings given by Gold et al.[19] and Kalinowska et al.[20]

The pleomorphic adenoma in our study showed an oval shape with partially unclear boundaries, mixed echo-intensity, and heterogeneous structure with posterior echoes being attenuated having mixed content with no vascularity. The partially unclear boundaries in our case can be contributed due to the long standing nature of pleomorphic adenoma in our patient. The rest findings were similar as found in the study by Chandak et al.,[2] Rajesh et al.,[15] and Gritzman et al.[16]

The characteristic sonographic appearance of the head and neck lipomas is that of an elliptical mass parallel to the skin surface that is hyperechoic relative to adjacent muscle and that contains linear echogenic lines at right angles to the ultrasound beam. Lipoma in our case was having oval shape with well-defined boundaries, heterogeneous eco intensity, and heterogeneous structure with echogenic lines and solid content similar to those found in study by Ahuja et al.[21] and Chandak et al.[2]

In total 5 cases of malignant swellings, 4 were having metastatic lymph node and 1 was mucoepidermoid carcinoma involving sublingual salivary gland. Out of 4 metastatic lymph nodes, 2 were having an oval shape and 2 were having round shape with 3 having relatively clear boundary and 1 having partially unclear boundary, 3 were having mixed internal structure and 1 was having hypoechoic structure, with heterogenous architecture and internal central necrosis, 2 having unchanged posterior echoes, and 3 having mixed content with no vascularity noted. The findings were similar to that found by Ying and Ahuja [17] and Chandak et al.[2]

In mucoepidermoid carcinoma, the sonography revealed round shape with well-defined borders with mixed echo-intensity, heterogenous structure with enhanced posterior echoes mixed content, and vascularity noted in the periphery of the lesion. The findings were similar to that found by Rajesh et al.[15] and Gritzman et al.[16]

Provisionally, only 2 were diagnosed as metastatic lymphadenitis, 1 swelling was misdiagnosed as inflammatory due to the clinical appearance of the swelling, i.e., reddish appearance of the overlying skin and increase in local temperature of the swelling. One swelling was misdiagnosed as ranula because of the characteristic location of the swelling and 1 swelling was misdiagnosed as tuberculous lymphadenitis due to history of the swelling of patient and palpation findings.

USG misdiagnosed 1 swelling as tuberculous lymphadenitis due to its similar USG features with malignant lymphadenitis.[17],[22],[23] Hence, it can be said that USG is safe, inexpensive, and effective investigation tool in diagnosing soft tissue swelling of the head and neck.

Considering the drawback of the study, it only had a single observer. Hence, more accuracy regarding use of USG could be obtained by increasing the sample size and also by increasing the number of observers.

Conclusion

From the present study, it can be concluded that USG is highly accurate in diagnosing benign neoplasms, followed by soft tissue cystic swellings and malignant neoplasms, followed by inflammatory swellings of the head and neck region.

Declaration of patient consent

The authors certify that they have obtained all appropriate patient consent forms. In the form the patient(s) has/have given his/her/their consent for his/her/their images and other clinical information to be reported in the journal. The patients understand that their names and initials will not be published and due efforts will be made to conceal their identity, but anonymity cannot be guaranteed.